Control system for producing signals of various frequencies



Aug. 20, 1929. w, c, BEACH 1,724,900

CONTROL SYSTEM FOR PRODUCING SIGNALS OF VARIOUS FREQUENCIES Filed Aug.18, 1924 Patented Aug. 20, 1929.

UNITED STATES 1,724,900 PATENT OFFICE.

WILLIAM C. BEACH, F BLOOMFIELD, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRICCOMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

CONTROL SYSTEM FOR PRODUCING SIGNALS OF VARIOUS FREQUENCIES.

Application filed August 18, 1924. Serial No. 732,673.

This invention relates to a signaling system for use in automatictelephone systems.

It is an object of this invention to provide an im roved signalingsystem.

In telephone exchange systems, particularly of the automaticallyoperated type, a

- large variety of signals is required and various tones, such as dialtone, busy tone, etc., are used to acquaint the subscriber withconditions that are encountered during the op eration of central ofliceapparatus for service connections. It is important that a tone used forany given purpose be of the same frequency and pitch in all circuits,and to obtain this same tone under various conditions, an adjustabletone producing circuit is an essential improvement.

The utility of a control system for producing signals of variousfrequencies is great since a standard apparatus combination may be usedin various types of circuits associated with subscribers or operatorsapparatus for many purposes. It is well known that any part of asystemthat is standardized affords economy.

A feature of this invention relates to the use of an improved electricalcontrol system for producing signals of various frequencies.

This and other features of the invention will be apparent from thefollowing description, taken in connection with accompanying drawing.

While the invention has been disclosed as particularly adapted forsignals in an automatically operated telephone system. it will beapparent from the following description that the invention has a widerutility and that by slight modification, it may be adapted for use withother types of apparatus in which an adjustable signaling system isrequired.

Fig. 1 of the drawing illustrates the pre ferred form of apparatus fortransmitting a tone through a receiver, including adjustable apparatusfor changing the frequency and pitch of the tone. Figs. 2, 3 and 4illustrate alternative forms of the same structure, in which Figs. 2 and3 show apparatus for transmitting a tone inductively to a receiver andFig. 4 shows apparatus for flashing a lamp.

Let it be assumed that it is desirable to transmit a tone of a givenfrequency and pitch through receiver 5. Fig. 1. The oper ation of key 1establishes a circuit from grounded battery through the winding andcontact of relay 6, variable resistance 3 to ground through the contactof key 1. Upon the operation of relay 6, its operating circuit is openedat its contact. At this time, condenser 2 is charged from groundedbattery through the winding of relay 6. This charging current maintainsrelay 6 in an operated position until the condenser is charged to apoint where the current flow has dimin ished to the releasing adjustmentof relay 6. The release of relay 6 reestablishes its operating circuitand establishes a discharge cir cuit for condenser 2 through resistance3. The resistance 3 regulates the amount of current permitted to passthrough the winding circuit for relay 6 is not effective since the Hcondenser charge acts as a shunt to prevent the operation of the relay.As the potential of the condenser charge decreases, the current throughthe winding of relay 6 increases until the current is strong enough tocause the relay to attract its armature. The foregoing operatingsequence continues until key 1 is released. The duration of time thatrelay 6 is held in an operated position is dependent upon thecapacity ofcondenser 2. The continued operation and release of relay 6 produces atone which is transmitted through condenser 4 and receiver 5. Condenser4 is of such capacity that the releasing time constant of relay 6 is notmaterially afi'ected thereby. I

Condenser 2 and resistance 3 may be varied to control the operating andreleasing time constants of relay 6. By controlling the time constantsof relay 6 the frequency of the tone source may be varied with ordinaryapparatus from 15 to 1000 interruptions per second and thus the tonepitch may be widely varied. By using a specially designed relay in lieuof relay 6 these variations in tone can be made much greater.

The operator of the circuit of Fig. 2 is the same as for Fig. 1 with theexception that relay 7 has two windings inductively associated. A tonecurrent as described for Fig. 1 is produced in the left winding of relay7 and induced into the right Winding for transmission through receiver5.

The operation of the circuit of Fig. 3 is the same as that described forFig. 1 With the exception that the operating circuit for relay 8 iscarried through the left Winding of inductive coil 9. The tone currentproduced in the left Winding of coil 9 is transmitted by inductance tothe right Winding of coil 9 and thence through receiver 5.

The operation of relay 10, shown in Fig. 4, is the same as thatdescribed for relay 6 of Fig. 1. In this circuit combination, contact 11is closed upon the operation of key 1. Relay 10 in its normal positionestablishes a circuit to light lamp 12 from ground through the rightvcontact of said relay, contact 11, lamp 12 to grounded battery. Uponeach operation of relay 10, lamp 12 is extinguished. The capacity ofcondenser 2 and the resistance of coil 3 may be changed to vary thefrequency of flashing lamp 12.

While the contact used to establish an op erating circuit for relays 6,7, 8 and 10 is shown as a key, it Will be apparent that this contact maybe associated With a relay or the frequency of electrical oscillationsin an electrical circuit comprising an electromagnet havmg an armature,an-energizlngcircuit for said electromagnet, a holding circuit includinga capacity, and means for adjusting said capacity to determine the rateof release of said device and thereby controlling the. frequency of theoscillations produced.

2. Adevice for producing electrical oscillations in an electricalcircuit comprising an electromagnetic device having a Winding, acondenser adapted to be connected in series With said Winding and asource of potential, means to vary the rate of charging of saidcondenser-during its connection to said source of potential andconsequently the periodicity of said electromagnetic device, and adischarge path for said condenser independent of said device.

3. A device for producing and controlling the frequency of electricaloscillations in an electrical circuit comprising an electromagnet, anarmature and contact, an energizing circuit for said magnet includingsaid armature and contact, an independent holding circuit for saidmagnet including a condenser,

and means to vary the capacity of said condenser to control the rate ofrelease of said magnet. i

4. A device for producing and controlling the frequency of electricaloscillations in an electrical circuit comprising an electromagnet havingan armature, an energizing circuit for said electromagnet including aresistance, a holding circuit including a condenser of variablecapacity, means for adjusting said resistance to determine the time ofenergization of said-device, and means for adjusting said capacity todetermine the rate of release of said device and thereby controlling thefrequency of the oscillations produced.

5. A device for producing electrical oscillations in an electricalcircuit comprising an electromagnetic device having a Winding, acondenser adapted to be connected in series with said Winding and asource of potential, means for varying the rate of charging saidcondenser during its connection to said source of potential forcontrolling the periodicity of said electromagnetic device, and means tovary the rate of discharging said condenser for further controlling theperiodicity of said electromagnetic device.

6. A device for producing and controlling the frequency of electricaloscillations in an electrical circuit comprising an electromagnet, aprimary energizing circuit for said electromagnet including aresistance, a secondary circuit for said electromagnet includ ing acondenser, means to progressively establishsaid primary and saidsecondary cii= cuits for respectively energizing said electromagnet andfor sustaining energy in said electromagnet for a time period dependingon the capacity of said condenser, a discharge circuit for saidcondenser including said resistance arranged to retard the energizationof said. electromagnet, and means to adjust said resistance to regulatethe periodicity of said device.

7. A device for producing and controlling the frequency of electricaloscillations in an electrical circuit comprising an electromagnet, aprimary energizing circuit for said electromagnet including aresistance, a secondary circuit for said electromagnet including acondenser, means to progressively establish said primary and secondaryci Quits for respectively energizing said electromagnet and forsustaining energy in said electroe magnet under the control of thepotential in crease in said condenser, a discharge circuit for saidcondenser including said resistance arranged to retard the energizationof said electromagnet, means to adjust said condenser to regulatethepossible potential increase,

and means to adjust said resistance to regu- 7 late the rate ofdischarge of said condenser thereby controlling the frequency ofoscillations produced.

8. A device for producing and controlling the frequency of electricaloscillations in an electrical circuit comprising an electromagnet, aprimary energizing circuit for said electromagnetincluding a resistance,a condenser of variable capacity, a charging circuit for said condenserincluding said electromagnet for maintaining the energizauion of saidelectromagnet throughout the period of charging, a discharge circuit forsaid condenser arranged to retard the energization of said electromagnetover said primary circuit, means to adjust the capacity of saidcondenser to vary the period of sustained energization of said device,and means to adjust said resistance to vary the rate of discharge ofsaid condenser for controlling the time of energizing said device.

9. A device for producing and controlling the frequency of electricaloscillations in an electrical system comprising an electromagnet, aprimary energizing circuit for said electromagnet including aresistance, a condenser of variable capacity, a charging circuit forsaid condenser including said electromagnet for maintaining theenergization of said electromagnet throughout the period of charging, adischarge circuit for said condenser arranged to retard the energizationof said electromagnet over said primary circuit, means to adjust thecapacity of said condenser to vary the period of sustained energizationof said device, and means to adjust said resistance to compensate forvarious adjustments of said condenser to maintain a constant rate ofdischarge of said condenser for controlling the periodicity of saiddevice.

10. A device for producing and controlling the frequency of electricaloscillations in an electrical circuit comprising an electromagnet havinga normally closed contact, an energizing circuit for said electromagnetincluding a resistance, a holding circuit for said electromagnetincluding a condenser, means for establishing said circuits for openingand closing said contact, means for adjusting said resistance to controlthe closed period of said contact, and means to adjust the capacity ofsaid condenser to control the open period of said contact.

11.-A device for producing and controlling the frequency of theelectrical oscillations in an electrical circuit comprising anelectromagnet having a normally closed contact, a primary energizingcircuit for said electromagnet including a resistance and said contact,a secondary circuit for said electromagnet including a variablecondenser normally shunted by said resistance, means to establish saidprimary circuit for opening said contact thereby establishing saidsecondary circuit for sustaining energy in said electromagnet for a timeperiod depending upon the capacity of said condenser, a dischargecircuit for said condenser including said contact and resistancearranged to retard the energization of said electromagnet, and means toadjust said resistance to regulate the rate of discharge of saidcondenser for controlling the periodicity of said device.

12. A device for producing and controll ip g the frequency of electricaloscillations in an electrical circuit comprising an electromagnet havinga normally closed contact, a primary energizing circuit for saidelectromagnet including a resistance and said contact, a secondarycircuit for said electromagnet. including a condenser, means toestablish said primary circuit for opening said contact therebyestablishing said secondary circuit for sustaining energy in saidelectromagnet for a time period depending upon the release adjustment ofsaid electromagnet, a discharge circuit for said condenser includingsaid contact and resistance arranged to retard the energization of saidelectromagnet, and means to adjust said resistance to regulate the rateof discharge otsaid condenser for controlling the periodicity of saiddevice.

13. A device for producing and controlling the frequency of theelectrical oscillations in an electrical circuit comprising anelectromagnet having a normally closed contact, a primary energizingcircuit for said electromagnetincluding a resistance and said contact, asecondary circuit for said electromagnet including a variable condensernormally shunted by said resistance, means to establish said primarycircuit for opening said contact thereby establishing said secondarycircuit for sustaining energy in said electromagnet for a time perioddepending upon the capacity of said condenser, a dis charge circuit forsaid condenser including said contact and resistance arranged to retardthe energization of said electromagnet, and means to either adjust theresistance or the capacity of said condenser for controlling theperiodicity of said device.

14. A device for producing and controlling the frequency of electricaloscillations in an electrical circuit comprising an electromagnet havinga normally closed contact associated with said electrical circuit, aprimary energizing circuit for said electromagnet including saidresistance and contact, a secondary circuit for said electromagnetincluding a condenser, means to progressively establish said primary andsecondary circuits for respectively energizing said electromagnet foropening said contacts and for sustaining energy in said electromagnetfor a time period depending upon the release adjustment of saidelectromagnet, a dis charge circuit for said condenser including saidresistance and contact arranged to retard the energization of saidelectromagnet, and means to adjust said resistance to regulate the rateof discharge of said condenser for controlling the periodicity of saidcontact movement.

In Witness whereof, I hereunto subscribe my name this 15th day of AugustA. D., 1924.

WILLIAM C. BEACH.

